1. Field of the Invention
This invention relates generally to sheet metal fabrication and more particularly to a method of providing simulated holes in sheet metal without drilling or punching.
2. Description of the Prior Art
In fabricating structures from sheet metal such as enclosures for electrical apparatus there is a cost motivation to reduce the sheet metal gauge to the smallest practical metal thickness. Structural strength is typically attained by folding the thin sheet metal. Where column strength is required, as in a corner, the sheet metal may have a multi-bend, or convoluted final shape. A commonly used manufacturing method is "roll forming", where sheet metal passes through groups of rollers in series, to gradually create the shapes required. Using mechanical screw fasteners in fabrication presents a problem because the sheet metal is not thick enough to provide the necessary threads to anchor the fastener in place. Screw and nut combinations are required which increases the cost of fabrication.